The commonly used brakes found on exercising devices are of the frictional type, the hydraulic type, the air resistance type or the generator type. However, the frictional type is easily worn out and does not provide a smooth resistance force. As for the hydraulic type, there are the problems of oil leaking, noise and insufficient braking torque at high temperature. Regarding the air resistance type, they are too large in size and are difficult to adjust. The generator types are formed by a complicated structure and are very costly.
It is, therefore, an object of the present invention to provide a magnetic brake which may obviate and mitigate the above-mentioned drawbacks.